Raman spectroscopy has emerged as a leading technique for the analysis of the structure of inorganic materials and complex organic molecules. Scientists engaged in the application of Raman spectroscopy have found that by decorating a surface, upon which a molecule is later adsorbed, with a thin layer of a metal in which surface plasmons have frequencies in a range of electromagnetic radiation used to excite such a molecule and in which surface plasmons have frequencies in a range of electromagnetic radiation emitted by such a molecule, it is possible to enhance the intensity of a Raman spectrum of such a molecule. This technique has been termed surface enhanced Raman spectroscopy (SERS).
In addition, spectroscopists utilizing spectroscopic techniques for the analysis of molecular structures have a continuing interest in improving the sensitivity of their spectroscopic techniques. Not only is improved sensitivity desirable for reducing the time of analysis, but also improved sensitivity can provide previously unachievable results. For example, improved sensitivity is directly related to lower detectability limits for previously undetected molecular constituents. Thus, scientists engaged in the application of Raman spectroscopy are motivated to improve the sensitivity of SERS for the detection of molecules and the spectral signatures of moieties in these molecules.
The drawings referred to in this description should not be understood as being drawn to scale unless specifically noted.